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Camera sensor defect correction and noise reduction

Camera sensor defect correction and noise reduction description/claims

Digital cameras include at least one camera sensor, such as, e.g., a charge coupled device or “CCD” or complementary metal oxide semiconductor (CMOS) sensor. The digital camera includes a plurality of photosensitive cells, each of which builds-up or accumulates an electrical charge in response to exposure to light. The accumulated electrical charge for any given pixel is proportional to the intensity and duration of the light exposure, and is used to generate digital photographs.

Camera sensors have defects, perhaps thousands of defective pixels in a camera sensor having millions of pixels. These defective pixels may be identified during a calibration procedure in which the location of defective pixels is stored in a list on the camera itself. When the camera is used to take pictures, the defective pixels are blurred using pixel data from surrounding “good” pixels.

However, the list of defective pixels uses limited storage space on the camera. In addition, pixels that were determined to be “good” pixels during calibration, may later become defective during camera use. Furthermore, pixels that were determined to be defective pixels during calibration may actually be “good” pixels under different conditions during camera use.

FIG. 1 is a component diagram of an exemplary camera system.

FIG. 2 is a high-level diagram of an exemplary camera sensor.

FIG. 3 is a high-level diagram of an exemplary camera sensor illustrating pixel data which may be used for cameras sensor defect correction and noise reduction.

FIG. 4 is a flowchart illustrating exemplary operations which may be implemented for camera sensor defect correction and noise reduction.

Systems and methods are disclosed herein for camera sensor defect correction and noise reduction. In an exemplary embodiment, an “on-the-fly” method may be implemented for identifying defective pixels for each image (or at least selected images) generated during camera use by comparing each pixel to all neighboring pixels. If the pixel is indeed defective, it is corrected using pixel data from surrounding pixels using traditional techniques (e.g., interpolation among neighboring pixel values or “blurring,” median filtering, etc.). If the pixel is “good” (e.g., the anomaly is part of the picture and not a pixel defect), the actual pixel data is used for the image.

As used herein the term “defective pixel” and pixels affected by “noise” means any pixel value which is significantly different than what should be recorded to represent the scene being photographed.

FIG. 1 is a component diagram of an exemplary camera system 100. Although reference is made to a particular digital still-photo camera system 100, it is noted that the systems and methods described herein for identifying camera sensors may be implemented with any of a wide range of digital still-photo and/or video cameras, now known or that may be later developed. In yet other embodiments, sensor defect correction and noise reduction may also be used for the sensors of other imaging devices (e.g., scanners, medical imaging, etc.).

Exemplary camera system 100 may include a lens 120 positioned in the camera system 100 to focus light 130 reflected from one or more objects 140 in a scene 145 onto a camera sensor 150. Exemplary lens 120 may be any suitable lens which focuses light 130 reflected from the scene 145 onto camera sensor 150.

Camera system 100 may also include image capture logic 160. In digital cameras, the image capture logic 160 reads out the charge build-up from the camera sensor 150. The image capture logic 160 generates image data signals representative of the light 130 captured during exposure to the scene 145. The image data signals may be implemented by the camera for auto-focusing, auto-exposure, pre-flash calculations, image stabilizing, and/or detecting white balance, to name only a few examples.

The camera system 100 may be provided with signal processing logic 170 operatively associated with the image capture logic 160, and optionally, with camera settings 180. The signal processing logic 170 may receive as input image data signals from the image capture logic 160. Signal processing logic 170 may be implemented to perform various calculations or processes on the image data signals, e.g., for output on the display 190.

In addition, the signal processing logic 170 may also generate output for other devices and/or logic in the camera system 100. For example, the signal processing logic 170 may generate control signals for output to exposure control module 155 to adjust exposure time of the camera sensor 150 (e.g., varying exposure time). Signal processing logic 170 may also receive information from the exposure control module 155.

• Provisional Patent
• Utility Patent

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